(4-x)/(x-5)-1+4/x≥0
(4x-x²-x²+5x+4x-20)/x(x-5)≥0
(-2x²+13x-20)/x(x-5)≥0
(2x²-13x+20)/x(x-5)≤0
2x²-13x+20=0
D=169-160=9
x1=(13-3)/4=2,5
x2=(13+3)/4=4
x=0
x=5
+ _ + _ +
---------(0)---------[2,5]---------[4]------------(5)-----------------
x∈(0;2,5] U [4;5)